src/work/alpar/list_graph.h
author athos
Mon, 03 May 2004 14:43:49 +0000
changeset 514 fd991a24c857
parent 503 769f31e9f7b0
child 515 a7eeb8af6b34
permissions -rw-r--r--
An awful mistake found and corrected.
     1 // -*- mode:C++ -*-
     2 
     3 #ifndef HUGO_LIST_GRAPH_H
     4 #define HUGO_LIST_GRAPH_H
     5 
     6 ///\ingroup graphs
     7 ///\file
     8 ///\brief ListGraph, SymListGraph, NodeSet and EdgeSet classes.
     9 
    10 #include <vector>
    11 #include <limits.h>
    12 
    13 #include "invalid.h"
    14 
    15 namespace hugo {
    16 
    17 /// \addtogroup graphs
    18 /// @{
    19 
    20   class SymListGraph;
    21 
    22   ///A list graph class.
    23 
    24   ///This is a simple and fast erasable graph implementation.
    25   ///
    26   ///It conforms to the graph interface documented under
    27   ///the description of \ref GraphSkeleton.
    28   ///\sa \ref GraphSkeleton.
    29   class ListGraph {
    30 
    31     //Nodes are double linked.
    32     //The free nodes are only single linked using the "next" field.
    33     struct NodeT 
    34     {
    35       int first_in,first_out;
    36       int prev, next;
    37       //      NodeT() {}
    38     };
    39     //Edges are double linked.
    40     //The free edges are only single linked using the "next_in" field.
    41     struct EdgeT 
    42     {
    43       int head, tail;
    44       int prev_in, prev_out;
    45       int next_in, next_out;
    46       //FIXME: is this necessary?
    47       //      EdgeT() : next_in(-1), next_out(-1) prev_in(-1), prev_out(-1) {}  
    48     };
    49 
    50     std::vector<NodeT> nodes;
    51     //The first node
    52     int first_node;
    53     //The first free node
    54     int first_free_node;
    55     std::vector<EdgeT> edges;
    56     //The first free edge
    57     int first_free_edge;
    58     
    59   protected:
    60     
    61     template <typename Key> class DynMapBase
    62     {
    63     protected:
    64       const ListGraph* G; 
    65     public:
    66       virtual void add(const Key k) = NULL;
    67       virtual void erase(const Key k) = NULL;
    68       DynMapBase(const ListGraph &_G) : G(&_G) {}
    69       virtual ~DynMapBase() {}
    70       friend class ListGraph;
    71     };
    72     
    73   public:
    74     template <typename T> class EdgeMap;
    75     template <typename T> class NodeMap;
    76     
    77     class Node;
    78     class Edge;
    79 
    80     //  protected:
    81     // HELPME:
    82   protected:
    83     ///\bug It must be public because of SymEdgeMap.
    84     ///
    85     mutable std::vector<DynMapBase<Node> * > dyn_node_maps;
    86     ///\bug It must be public because of SymEdgeMap.
    87     ///
    88     mutable std::vector<DynMapBase<Edge> * > dyn_edge_maps;
    89     
    90   public:
    91 
    92     class NodeIt;
    93     class EdgeIt;
    94     class OutEdgeIt;
    95     class InEdgeIt;
    96     
    97     template <typename T> class NodeMap;
    98     template <typename T> class EdgeMap;
    99     
   100   public:
   101 
   102     ListGraph() : nodes(), first_node(-1),
   103 		  first_free_node(-1), edges(), first_free_edge(-1) {}
   104     ListGraph(const ListGraph &_g) : nodes(_g.nodes), first_node(_g.first_node),
   105 				     first_free_node(_g.first_free_node),
   106 				     edges(_g.edges),
   107 				     first_free_edge(_g.first_free_edge) {}
   108     
   109     ~ListGraph()
   110     {
   111       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
   112 	  i!=dyn_node_maps.end(); ++i) (**i).G=NULL;
   113       for(std::vector<DynMapBase<Edge> * >::iterator i=dyn_edge_maps.begin();
   114 	  i!=dyn_edge_maps.end(); ++i) (**i).G=NULL;
   115     }
   116 
   117     int nodeNum() const { return nodes.size(); }  //FIXME: What is this?
   118     int edgeNum() const { return edges.size(); }  //FIXME: What is this?
   119 
   120     ///\bug This function does something different than
   121     ///its name would suggests...
   122     int maxNodeId() const { return nodes.size(); }  //FIXME: What is this?
   123     ///\bug This function does something different than
   124     ///its name would suggests...
   125     int maxEdgeId() const { return edges.size(); }  //FIXME: What is this?
   126 
   127     Node tail(Edge e) const { return edges[e.n].tail; }
   128     Node head(Edge e) const { return edges[e.n].head; }
   129 
   130     Node aNode(OutEdgeIt e) const { return edges[e.n].tail; }
   131     Node aNode(InEdgeIt e) const { return edges[e.n].head; }
   132 
   133     Node bNode(OutEdgeIt e) const { return edges[e.n].head; }
   134     Node bNode(InEdgeIt e) const { return edges[e.n].tail; }
   135 
   136     NodeIt& first(NodeIt& v) const { 
   137       v=NodeIt(*this); return v; }
   138     EdgeIt& first(EdgeIt& e) const { 
   139       e=EdgeIt(*this); return e; }
   140     OutEdgeIt& first(OutEdgeIt& e, const Node v) const { 
   141       e=OutEdgeIt(*this,v); return e; }
   142     InEdgeIt& first(InEdgeIt& e, const Node v) const { 
   143       e=InEdgeIt(*this,v); return e; }
   144 
   145 //     template< typename It >
   146 //     It first() const { It e; first(e); return e; }
   147 
   148 //     template< typename It >
   149 //     It first(Node v) const { It e; first(e,v); return e; }
   150 
   151     bool valid(Edge e) const { return e.n!=-1; }
   152     bool valid(Node n) const { return n.n!=-1; }
   153     
   154     void setInvalid(Edge &e) { e.n=-1; }
   155     void setInvalid(Node &n) { n.n=-1; }
   156     
   157     template <typename It> It getNext(It it) const
   158     { It tmp(it); return next(tmp); }
   159 
   160     NodeIt& next(NodeIt& it) const { 
   161       it.n=nodes[it.n].next; 
   162       return it; 
   163     }
   164     OutEdgeIt& next(OutEdgeIt& it) const
   165     { it.n=edges[it.n].next_out; return it; }
   166     InEdgeIt& next(InEdgeIt& it) const
   167     { it.n=edges[it.n].next_in; return it; }
   168     EdgeIt& next(EdgeIt& it) const {
   169       if(edges[it.n].next_in!=-1) { 
   170 	it.n=edges[it.n].next_in;
   171       }
   172       else {
   173 	int n;
   174 	for(n=nodes[edges[it.n].head].next;
   175 	    n!=-1 && nodes[n].first_in == -1;
   176 	    n = nodes[n].next) ;
   177 	it.n = (n==-1)?-1:nodes[n].first_in;
   178       }
   179       return it;
   180     }
   181 
   182     int id(Node v) const { return v.n; }
   183     int id(Edge e) const { return e.n; }
   184 
   185     /// Adds a new node to the graph.
   186 
   187     /// \todo It adds the nodes in a reversed order.
   188     /// (i.e. the lastly added node becomes the first.)
   189     Node addNode() {
   190       int n;
   191       
   192       if(first_free_node==-1)
   193 	{
   194 	  n = nodes.size();
   195 	  nodes.push_back(NodeT());
   196 	}
   197       else {
   198 	n = first_free_node;
   199 	first_free_node = nodes[n].next;
   200       }
   201       
   202       nodes[n].next = first_node;
   203       if(first_node != -1) nodes[first_node].prev = n;
   204       first_node = n;
   205       nodes[n].prev = -1;
   206       
   207       nodes[n].first_in = nodes[n].first_out = -1;
   208       
   209       Node nn; nn.n=n;
   210 
   211       //Update dynamic maps
   212       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
   213 	  i!=dyn_node_maps.end(); ++i) (**i).add(nn);
   214 
   215       return nn;
   216     }
   217     
   218     Edge addEdge(Node u, Node v) {
   219       int n;
   220       
   221       if(first_free_edge==-1)
   222 	{
   223 	  n = edges.size();
   224 	  edges.push_back(EdgeT());
   225 	}
   226       else {
   227 	n = first_free_edge;
   228 	first_free_edge = edges[n].next_in;
   229       }
   230       
   231       edges[n].tail = u.n; edges[n].head = v.n;
   232 
   233       edges[n].next_out = nodes[u.n].first_out;
   234       if(nodes[u.n].first_out != -1) edges[nodes[u.n].first_out].prev_out = n;
   235       edges[n].next_in = nodes[v.n].first_in;
   236       if(nodes[v.n].first_in != -1) edges[nodes[v.n].first_in].prev_in = n;
   237       edges[n].prev_in = edges[n].prev_out = -1;
   238 	
   239       nodes[u.n].first_out = nodes[v.n].first_in = n;
   240 
   241       Edge e; e.n=n;
   242 
   243       //Update dynamic maps
   244       for(std::vector<DynMapBase<Edge> * >::iterator i=dyn_edge_maps.begin();
   245 	  i!=dyn_edge_maps.end(); ++i) (**i).add(e);
   246 
   247       return e;
   248     }
   249 
   250   private:
   251     void eraseEdge(int n) {
   252       
   253       if(edges[n].next_in!=-1)
   254 	edges[edges[n].next_in].prev_in = edges[n].prev_in;
   255       if(edges[n].prev_in!=-1)
   256 	edges[edges[n].prev_in].next_in = edges[n].next_in;
   257       else nodes[edges[n].head].first_in = edges[n].next_in;
   258       
   259       if(edges[n].next_out!=-1)
   260 	edges[edges[n].next_out].prev_out = edges[n].prev_out;
   261       if(edges[n].prev_out!=-1)
   262 	edges[edges[n].prev_out].next_out = edges[n].next_out;
   263       else nodes[edges[n].tail].first_out = edges[n].next_out;
   264       
   265       edges[n].next_in = first_free_edge;
   266       first_free_edge = -1;      
   267 
   268       //Update dynamic maps
   269       Edge e; e.n=n;
   270       for(std::vector<DynMapBase<Edge> * >::iterator i=dyn_edge_maps.begin();
   271 	  i!=dyn_edge_maps.end(); ++i) (**i).erase(e);
   272     }
   273       
   274   public:
   275 
   276     void erase(Node nn) {
   277       int n=nn.n;
   278       
   279       int m;
   280       while((m=nodes[n].first_in)!=-1) eraseEdge(m);
   281       while((m=nodes[n].first_out)!=-1) eraseEdge(m);
   282 
   283       if(nodes[n].next != -1) nodes[nodes[n].next].prev = nodes[n].prev;
   284       if(nodes[n].prev != -1) nodes[nodes[n].prev].next = nodes[n].next;
   285       else first_node = nodes[n].next;
   286       
   287       nodes[n].next = first_free_node;
   288       first_free_node = n;
   289 
   290       //Update dynamic maps
   291       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
   292 	  i!=dyn_node_maps.end(); ++i) (**i).erase(nn);
   293     }
   294     
   295     void erase(Edge e) { eraseEdge(e.n); }
   296 
   297     ///\bug Dynamic maps must be updated!
   298     ///
   299     void clear() {
   300       nodes.clear();edges.clear();
   301       first_node=first_free_node=first_free_edge=-1;
   302     }
   303 
   304     class Node {
   305       friend class ListGraph;
   306       template <typename T> friend class NodeMap;
   307        
   308       friend class Edge;
   309       friend class OutEdgeIt;
   310       friend class InEdgeIt;
   311       friend class SymEdge;
   312 
   313     protected:
   314       int n;
   315       friend int ListGraph::id(Node v) const; 
   316       Node(int nn) {n=nn;}
   317     public:
   318       Node() {}
   319       Node (Invalid) { n=-1; }
   320       bool operator==(const Node i) const {return n==i.n;}
   321       bool operator!=(const Node i) const {return n!=i.n;}
   322       bool operator<(const Node i) const {return n<i.n;}
   323     };
   324     
   325     class NodeIt : public Node {
   326       friend class ListGraph;
   327     public:
   328       NodeIt() : Node() { }
   329       NodeIt(Invalid i) : Node(i) { }
   330       NodeIt(const ListGraph& G) : Node(G.first_node) { }
   331     };
   332 
   333     class Edge {
   334       friend class ListGraph;
   335       template <typename T> friend class EdgeMap;
   336 
   337       //template <typename T> friend class SymListGraph::SymEdgeMap;      
   338       //friend Edge SymListGraph::opposite(Edge) const;
   339       
   340       friend class Node;
   341       friend class NodeIt;
   342     protected:
   343       int n;
   344       friend int ListGraph::id(Edge e) const;
   345 
   346       Edge(int nn) {n=nn;}
   347     public:
   348       Edge() { }
   349       Edge (Invalid) { n=-1; }
   350       bool operator==(const Edge i) const {return n==i.n;}
   351       bool operator!=(const Edge i) const {return n!=i.n;}
   352       bool operator<(const Edge i) const {return n<i.n;}
   353       ///\bug This is a workaround until somebody tells me how to
   354       ///make class \c SymListGraph::SymEdgeMap friend of Edge
   355       int &idref() {return n;}
   356       const int &idref() const {return n;}
   357     };
   358     
   359     class EdgeIt : public Edge {
   360       friend class ListGraph;
   361     public:
   362       EdgeIt(const ListGraph& G) : Edge() {
   363       	int m;
   364 	for(m=G.first_node;
   365 	    m!=-1 && G.nodes[m].first_in == -1; m = G.nodes[m].next);
   366 	n = (m==-1)?-1:G.nodes[m].first_in;
   367       }
   368       EdgeIt (Invalid i) : Edge(i) { }
   369       EdgeIt() : Edge() { }
   370       ///\bug This is a workaround until somebody tells me how to
   371       ///make class \c SymListGraph::SymEdgeMap friend of Edge
   372       int &idref() {return n;}
   373     };
   374     
   375     class OutEdgeIt : public Edge {
   376       friend class ListGraph;
   377     public: 
   378       OutEdgeIt() : Edge() { }
   379       OutEdgeIt (Invalid i) : Edge(i) { }
   380 
   381       OutEdgeIt(const ListGraph& G,const Node v)
   382 	: Edge(G.nodes[v.n].first_out) {}
   383     };
   384     
   385     class InEdgeIt : public Edge {
   386       friend class ListGraph;
   387     public: 
   388       InEdgeIt() : Edge() { }
   389       InEdgeIt (Invalid i) : Edge(i) { }
   390       InEdgeIt(const ListGraph& G,Node v) :Edge(G.nodes[v.n].first_in){}
   391     };
   392 
   393     template <typename T> class NodeMap : public DynMapBase<Node>
   394     {
   395       std::vector<T> container;
   396 
   397     public:
   398       typedef T ValueType;
   399       typedef Node KeyType;
   400 
   401       NodeMap(const ListGraph &_G) :
   402 	DynMapBase<Node>(_G), container(_G.maxNodeId())
   403       {
   404 	G->dyn_node_maps.push_back(this);
   405       }
   406       NodeMap(const ListGraph &_G,const T &t) :
   407 	DynMapBase<Node>(_G), container(_G.maxNodeId(),t)
   408       {
   409 	G->dyn_node_maps.push_back(this);
   410       }
   411       
   412       NodeMap(const NodeMap<T> &m) :
   413  	DynMapBase<Node>(*m.G), container(m.container)
   414       {
   415  	G->dyn_node_maps.push_back(this);
   416       }
   417 
   418       template<typename TT> friend class NodeMap;
   419  
   420       ///\todo It can copy between different types.
   421       ///
   422       template<typename TT> NodeMap(const NodeMap<TT> &m) :
   423 	DynMapBase<Node>(*m.G)
   424       {
   425 	G->dyn_node_maps.push_back(this);
   426 	typename std::vector<TT>::const_iterator i;
   427 	for(typename std::vector<TT>::const_iterator i=m.container.begin();
   428 	    i!=m.container.end();
   429 	    i++)
   430 	  container.push_back(*i);
   431       }
   432       ~NodeMap()
   433       {
   434 	if(G) {
   435 	  std::vector<DynMapBase<Node>* >::iterator i;
   436 	  for(i=G->dyn_node_maps.begin();
   437 	      i!=G->dyn_node_maps.end() && *i!=this; ++i) ;
   438 	  //if(*i==this) G->dyn_node_maps.erase(i); //FIXME: Way too slow...
   439 	  //A better way to do that: (Is this really important?)
   440 	  if(*i==this) {
   441 	    *i=G->dyn_node_maps.back();
   442 	    G->dyn_node_maps.pop_back();
   443 	  }
   444 	}
   445       }
   446 
   447       void add(const Node k) 
   448       {
   449 	if(k.n>=int(container.size())) container.resize(k.n+1);
   450       }
   451 
   452       void erase(const Node) { }
   453       
   454       void set(Node n, T a) { container[n.n]=a; }
   455       //'T& operator[](Node n)' would be wrong here
   456       typename std::vector<T>::reference
   457       operator[](Node n) { return container[n.n]; }
   458       //'const T& operator[](Node n)' would be wrong here
   459       typename std::vector<T>::const_reference 
   460       operator[](Node n) const { return container[n.n]; }
   461 
   462       ///\warning There is no safety check at all!
   463       ///Using operator = between maps attached to different graph may
   464       ///cause serious problem.
   465       ///\todo Is this really so?
   466       ///\todo It can copy between different types.
   467       const NodeMap<T>& operator=(const NodeMap<T> &m)
   468       {
   469 	container = m.container;
   470 	return *this;
   471       }
   472       template<typename TT>
   473       const NodeMap<T>& operator=(const NodeMap<TT> &m)
   474       {
   475 	copy(m.container.begin(), m.container.end(), container.begin());
   476 	return *this;
   477       }
   478       
   479       void update() {}    //Useless for Dynamic Maps
   480       void update(T a) {}  //Useless for Dynamic Maps
   481     };
   482     
   483     template <typename T> class EdgeMap : public DynMapBase<Edge>
   484     {
   485       std::vector<T> container;
   486 
   487     public:
   488       typedef T ValueType;
   489       typedef Edge KeyType;
   490 
   491       EdgeMap(const ListGraph &_G) :
   492 	DynMapBase<Edge>(_G), container(_G.maxEdgeId())
   493       {
   494 	//FIXME: What if there are empty Id's?
   495 	//FIXME: Can I use 'this' in a constructor?
   496 	G->dyn_edge_maps.push_back(this);
   497       }
   498       EdgeMap(const ListGraph &_G,const T &t) :
   499 	DynMapBase<Edge>(_G), container(_G.maxEdgeId(),t)
   500       {
   501 	G->dyn_edge_maps.push_back(this);
   502       } 
   503       EdgeMap(const EdgeMap<T> &m) :
   504  	DynMapBase<Edge>(*m.G), container(m.container)
   505       {
   506  	G->dyn_edge_maps.push_back(this);
   507       }
   508 
   509       template<typename TT> friend class EdgeMap;
   510 
   511       ///\todo It can copy between different types.
   512       ///
   513       template<typename TT> EdgeMap(const EdgeMap<TT> &m) :
   514 	DynMapBase<Edge>(*m.G)
   515       {
   516 	G->dyn_edge_maps.push_back(this);
   517 	typename std::vector<TT>::const_iterator i;
   518 	for(typename std::vector<TT>::const_iterator i=m.container.begin();
   519 	    i!=m.container.end();
   520 	    i++)
   521 	  container.push_back(*i);
   522       }
   523       ~EdgeMap()
   524       {
   525 	if(G) {
   526 	  std::vector<DynMapBase<Edge>* >::iterator i;
   527 	  for(i=G->dyn_edge_maps.begin();
   528 	      i!=G->dyn_edge_maps.end() && *i!=this; ++i) ;
   529 	  //if(*i==this) G->dyn_edge_maps.erase(i); //Way too slow...
   530 	  //A better way to do that: (Is this really important?)
   531 	  if(*i==this) {
   532 	    *i=G->dyn_edge_maps.back();
   533 	    G->dyn_edge_maps.pop_back();
   534 	  }
   535 	}
   536       }
   537       
   538       void add(const Edge k) 
   539       {
   540 	if(k.n>=int(container.size())) container.resize(k.n+1);
   541       }
   542       void erase(const Edge) { }
   543       
   544       void set(Edge n, T a) { container[n.n]=a; }
   545       //T get(Edge n) const { return container[n.n]; }
   546       typename std::vector<T>::reference
   547       operator[](Edge n) { return container[n.n]; }
   548       typename std::vector<T>::const_reference
   549       operator[](Edge n) const { return container[n.n]; }
   550 
   551       ///\warning There is no safety check at all!
   552       ///Using operator = between maps attached to different graph may
   553       ///cause serious problem.
   554       ///\todo Is this really so?
   555       ///\todo It can copy between different types.
   556       const EdgeMap<T>& operator=(const EdgeMap<T> &m)
   557       {
   558 	container = m.container;
   559 	return *this;
   560       }
   561       template<typename TT>
   562       const EdgeMap<T>& operator=(const EdgeMap<TT> &m)
   563       {
   564 	copy(m.container.begin(), m.container.end(), container.begin());
   565 	return *this;
   566       }
   567       
   568       void update() {}    //Useless for DynMaps
   569       void update(T a) {}  //Useless for DynMaps
   570     };
   571 
   572   };
   573 
   574   ///Graph for bidirectional edges.
   575 
   576   ///The purpose of this graph structure is to handle graphs
   577   ///having bidirectional edges. Here the function \c addEdge(u,v) adds a pair
   578   ///of oppositely directed edges.
   579   ///There is a new edge map type called
   580   ///\ref SymListGraph::SymEdgeMap "SymEdgeMap"
   581   ///that complements this
   582   ///feature by
   583   ///storing shared values for the edge pairs. The usual
   584   ///\ref GraphSkeleton::EdgeMap "EdgeMap"
   585   ///can be used
   586   ///as well.
   587   ///
   588   ///The oppositely directed edge can also be obtained easily
   589   ///using \ref opposite.
   590   ///
   591   ///Here erase(Edge) deletes a pair of edges.
   592   ///
   593   ///\todo this date structure need some reconsiderations. Maybe it
   594   ///should be implemented independently from ListGraph.
   595 
   596   class SymListGraph : public ListGraph
   597   {
   598   public:
   599     template<typename T> class SymEdgeMap;
   600     template<typename T> friend class SymEdgeMap;
   601 
   602     SymListGraph() : ListGraph() { }
   603     SymListGraph(const ListGraph &_g) : ListGraph(_g) { }
   604     ///Adds a pair of oppositely directed edges to the graph.
   605     Edge addEdge(Node u, Node v)
   606     {
   607       Edge e = ListGraph::addEdge(u,v);
   608       ListGraph::addEdge(v,u);
   609       return e;
   610     }
   611 
   612     void erase(Node n) { ListGraph::erase(n); }
   613     ///The oppositely directed edge.
   614 
   615     ///Returns the oppositely directed
   616     ///pair of the edge \c e.
   617     Edge opposite(Edge e) const
   618     {
   619       Edge f;
   620       f.idref() = e.idref() - 2*(e.idref()%2) + 1;
   621       return f;
   622     }
   623     
   624     ///Removes a pair of oppositely directed edges to the graph.
   625     void erase(Edge e) {
   626       ListGraph::erase(opposite(e));
   627       ListGraph::erase(e);
   628     }
   629     
   630     ///Common data storage for the edge pairs.
   631 
   632     ///This map makes it possible to store data shared by the oppositely
   633     ///directed pairs of edges.
   634     template <typename T> class SymEdgeMap : public DynMapBase<Edge>
   635     {
   636       std::vector<T> container;
   637       
   638     public:
   639       typedef T ValueType;
   640       typedef Edge KeyType;
   641 
   642       SymEdgeMap(const SymListGraph &_G) :
   643 	DynMapBase<Edge>(_G), container(_G.maxEdgeId()/2)
   644       {
   645 	static_cast<const SymListGraph*>(G)->dyn_edge_maps.push_back(this);
   646       }
   647       SymEdgeMap(const SymListGraph &_G,const T &t) :
   648 	DynMapBase<Edge>(_G), container(_G.maxEdgeId()/2,t)
   649       {
   650 	G->dyn_edge_maps.push_back(this);
   651       }
   652 
   653       SymEdgeMap(const SymEdgeMap<T> &m) :
   654  	DynMapBase<SymEdge>(*m.G), container(m.container)
   655       {
   656  	G->dyn_node_maps.push_back(this);
   657       }
   658 
   659       //      template<typename TT> friend class SymEdgeMap;
   660 
   661       ///\todo It can copy between different types.
   662       ///
   663 
   664       template<typename TT> SymEdgeMap(const SymEdgeMap<TT> &m) :
   665 	DynMapBase<SymEdge>(*m.G)
   666       {
   667 	G->dyn_node_maps.push_back(this);
   668 	typename std::vector<TT>::const_iterator i;
   669 	for(typename std::vector<TT>::const_iterator i=m.container.begin();
   670 	    i!=m.container.end();
   671 	    i++)
   672 	  container.push_back(*i);
   673       }
   674  
   675       ~SymEdgeMap()
   676       {
   677 	if(G) {
   678 	  std::vector<DynMapBase<Edge>* >::iterator i;
   679 	  for(i=static_cast<const SymListGraph*>(G)->dyn_edge_maps.begin();
   680 	      i!=static_cast<const SymListGraph*>(G)->dyn_edge_maps.end()
   681 		&& *i!=this; ++i) ;
   682 	  //if(*i==this) G->dyn_edge_maps.erase(i); //Way too slow...
   683 	  //A better way to do that: (Is this really important?)
   684 	  if(*i==this) {
   685 	    *i=static_cast<const SymListGraph*>(G)->dyn_edge_maps.back();
   686 	    static_cast<const SymListGraph*>(G)->dyn_edge_maps.pop_back();
   687 	  }
   688 	}
   689       }
   690       
   691       void add(const Edge k) 
   692       {
   693 	if(!k.idref()%2&&k.idref()/2>=int(container.size()))
   694 	  container.resize(k.idref()/2+1);
   695       }
   696       void erase(const Edge k) { }
   697       
   698       void set(Edge n, T a) { container[n.idref()/2]=a; }
   699       //T get(Edge n) const { return container[n.idref()/2]; }
   700       typename std::vector<T>::reference
   701       operator[](Edge n) { return container[n.idref()/2]; }
   702       typename std::vector<T>::const_reference
   703       operator[](Edge n) const { return container[n.idref()/2]; }
   704 
   705       ///\warning There is no safety check at all!
   706       ///Using operator = between maps attached to different graph may
   707       ///cause serious problem.
   708       ///\todo Is this really so?
   709       ///\todo It can copy between different types.
   710       const SymEdgeMap<T>& operator=(const SymEdgeMap<T> &m)
   711       {
   712 	container = m.container;
   713 	return *this;
   714       }
   715       template<typename TT>
   716       const SymEdgeMap<T>& operator=(const SymEdgeMap<TT> &m)
   717       {
   718 	copy(m.container.begin(), m.container.end(), container.begin());
   719 	return *this;
   720       }
   721       
   722       void update() {}    //Useless for DynMaps
   723       void update(T a) {}  //Useless for DynMaps
   724 
   725     };
   726 
   727   };
   728   
   729 
   730   ///A graph class containing only nodes.
   731 
   732   ///This class implements a graph structure without edges.
   733   ///The most useful application of this class is to be the node set of an
   734   ///\ref EdgeSet class.
   735   ///
   736   ///It conforms to the graph interface documented under
   737   ///the description of \ref GraphSkeleton with the exception that you cannot
   738   ///add (or delete) edges. The usual edge iterators are exists, but they are
   739   ///always \ref INVALID.
   740   ///\sa \ref GraphSkeleton
   741   ///\sa \ref EdgeSet
   742   class NodeSet {
   743 
   744     //Nodes are double linked.
   745     //The free nodes are only single linked using the "next" field.
   746     struct NodeT 
   747     {
   748       int first_in,first_out;
   749       int prev, next;
   750       //      NodeT() {}
   751     };
   752 
   753     std::vector<NodeT> nodes;
   754     //The first node
   755     int first_node;
   756     //The first free node
   757     int first_free_node;
   758     
   759   protected:
   760     
   761     template <typename Key> class DynMapBase
   762     {
   763     protected:
   764       const NodeSet* G; 
   765     public:
   766       virtual void add(const Key k) = NULL;
   767       virtual void erase(const Key k) = NULL;
   768       DynMapBase(const NodeSet &_G) : G(&_G) {}
   769       virtual ~DynMapBase() {}
   770       friend class NodeSet;
   771     };
   772     
   773   public:
   774     template <typename T> class EdgeMap;
   775     template <typename T> class NodeMap;
   776     
   777     class Node;
   778     class Edge;
   779 
   780     //  protected:
   781     // HELPME:
   782   protected:
   783     ///\bug It must be public because of SymEdgeMap.
   784     ///
   785     mutable std::vector<DynMapBase<Node> * > dyn_node_maps;
   786     //mutable std::vector<DynMapBase<Edge> * > dyn_edge_maps;
   787     
   788   public:
   789 
   790     class NodeIt;
   791     class EdgeIt;
   792     class OutEdgeIt;
   793     class InEdgeIt;
   794     
   795     template <typename T> class NodeMap;
   796     template <typename T> class EdgeMap;
   797     
   798   public:
   799 
   800     ///Default constructor
   801     NodeSet() : nodes(), first_node(-1),
   802 		  first_free_node(-1) {}
   803     ///Copy constructor
   804     NodeSet(const NodeSet &_g) : nodes(_g.nodes), first_node(_g.first_node),
   805 				     first_free_node(_g.first_free_node) {}
   806     
   807     ~NodeSet()
   808     {
   809       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
   810 	  i!=dyn_node_maps.end(); ++i) (**i).G=NULL;
   811       //for(std::vector<DynMapBase<Edge> * >::iterator i=dyn_edge_maps.begin();
   812       //	  i!=dyn_edge_maps.end(); ++i) (**i).G=NULL;
   813     }
   814 
   815     int nodeNum() const { return nodes.size(); }  //FIXME: What is this?
   816     int edgeNum() const { return 0; }  //FIXME: What is this?
   817 
   818     ///\bug This function does something different than
   819     ///its name would suggests...
   820     int maxNodeId() const { return nodes.size(); }  //FIXME: What is this?
   821     ///\bug This function does something different than
   822     ///its name would suggests...
   823     int maxEdgeId() const { return 0; }  //FIXME: What is this?
   824 
   825     Node tail(Edge e) const { return INVALID; }
   826     Node head(Edge e) const { return INVALID; }
   827 
   828     Node aNode(OutEdgeIt e) const { return INVALID; }
   829     Node aNode(InEdgeIt e) const { return INVALID; }
   830 
   831     Node bNode(OutEdgeIt e) const { return INVALID; }
   832     Node bNode(InEdgeIt e) const { return INVALID; }
   833 
   834     NodeIt& first(NodeIt& v) const { 
   835       v=NodeIt(*this); return v; }
   836     EdgeIt& first(EdgeIt& e) const { 
   837       e=EdgeIt(*this); return e; }
   838     OutEdgeIt& first(OutEdgeIt& e, const Node v) const { 
   839       e=OutEdgeIt(*this,v); return e; }
   840     InEdgeIt& first(InEdgeIt& e, const Node v) const { 
   841       e=InEdgeIt(*this,v); return e; }
   842 
   843 //     template< typename It >
   844 //     It first() const { It e; first(e); return e; }
   845 
   846 //     template< typename It >
   847 //     It first(Node v) const { It e; first(e,v); return e; }
   848 
   849     bool valid(Edge e) const { return false; }
   850     bool valid(Node n) const { return n.n!=-1; }
   851     
   852     void setInvalid(Edge &e) { }
   853     void setInvalid(Node &n) { n.n=-1; }
   854     
   855     template <typename It> It getNext(It it) const
   856     { It tmp(it); return next(tmp); }
   857 
   858     NodeIt& next(NodeIt& it) const { 
   859       it.n=nodes[it.n].next; 
   860       return it; 
   861     }
   862     OutEdgeIt& next(OutEdgeIt& it) const { return it; }
   863     InEdgeIt& next(InEdgeIt& it) const { return it; }
   864     EdgeIt& next(EdgeIt& it) const { return it; }
   865 
   866     int id(Node v) const { return v.n; }
   867     int id(Edge e) const { return -1; }
   868 
   869     /// Adds a new node to the graph.
   870 
   871     /// \todo It adds the nodes in a reversed order.
   872     /// (i.e. the lastly added node becomes the first.)
   873     Node addNode() {
   874       int n;
   875       
   876       if(first_free_node==-1)
   877 	{
   878 	  n = nodes.size();
   879 	  nodes.push_back(NodeT());
   880 	}
   881       else {
   882 	n = first_free_node;
   883 	first_free_node = nodes[n].next;
   884       }
   885       
   886       nodes[n].next = first_node;
   887       if(first_node != -1) nodes[first_node].prev = n;
   888       first_node = n;
   889       nodes[n].prev = -1;
   890       
   891       nodes[n].first_in = nodes[n].first_out = -1;
   892       
   893       Node nn; nn.n=n;
   894 
   895       //Update dynamic maps
   896       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
   897 	  i!=dyn_node_maps.end(); ++i) (**i).add(nn);
   898 
   899       return nn;
   900     }
   901     
   902     void erase(Node nn) {
   903       int n=nn.n;
   904       
   905       if(nodes[n].next != -1) nodes[nodes[n].next].prev = nodes[n].prev;
   906       if(nodes[n].prev != -1) nodes[nodes[n].prev].next = nodes[n].next;
   907       else first_node = nodes[n].next;
   908       
   909       nodes[n].next = first_free_node;
   910       first_free_node = n;
   911 
   912       //Update dynamic maps
   913       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
   914 	  i!=dyn_node_maps.end(); ++i) (**i).erase(nn);
   915     }
   916     
   917     ///\bug Dynamic maps must be updated!
   918     ///
   919     void clear() {
   920       nodes.clear();
   921       first_node = first_free_node = -1;
   922     }
   923 
   924     class Node {
   925       friend class NodeSet;
   926       template <typename T> friend class NodeMap;
   927       
   928       friend class Edge;
   929       friend class OutEdgeIt;
   930       friend class InEdgeIt;
   931 
   932     protected:
   933       int n;
   934       friend int NodeSet::id(Node v) const; 
   935       Node(int nn) {n=nn;}
   936     public:
   937       Node() {}
   938       Node (Invalid i) { n=-1; }
   939       bool operator==(const Node i) const {return n==i.n;}
   940       bool operator!=(const Node i) const {return n!=i.n;}
   941       bool operator<(const Node i) const {return n<i.n;}
   942     };
   943     
   944     class NodeIt : public Node {
   945       friend class NodeSet;
   946     public:
   947       NodeIt(const NodeSet& G) : Node(G.first_node) { }
   948       NodeIt() : Node() { }
   949     };
   950 
   951     class Edge {
   952       //friend class NodeSet;
   953       //template <typename T> friend class EdgeMap;
   954 
   955       //template <typename T> friend class SymNodeSet::SymEdgeMap;      
   956       //friend Edge SymNodeSet::opposite(Edge) const;
   957       
   958       //      friend class Node;
   959       //      friend class NodeIt;
   960     protected:
   961       //friend int NodeSet::id(Edge e) const;
   962       //      Edge(int nn) {}
   963     public:
   964       Edge() { }
   965       Edge (Invalid) { }
   966       bool operator==(const Edge i) const {return true;}
   967       bool operator!=(const Edge i) const {return false;}
   968       bool operator<(const Edge i) const {return false;}
   969       ///\bug This is a workaround until somebody tells me how to
   970       ///make class \c SymNodeSet::SymEdgeMap friend of Edge
   971       //      int idref() {return -1;}
   972       //      int idref() const {return -1;}
   973     };
   974     
   975     class EdgeIt : public Edge {
   976       //friend class NodeSet;
   977     public:
   978       EdgeIt(const NodeSet& G) : Edge() { }
   979       EdgeIt (Invalid i) : Edge(i) { }
   980       EdgeIt() : Edge() { }
   981       ///\bug This is a workaround until somebody tells me how to
   982       ///make class \c SymNodeSet::SymEdgeMap friend of Edge
   983       //      int idref() {return -1;}
   984     };
   985     
   986     class OutEdgeIt : public Edge {
   987       friend class NodeSet;
   988     public: 
   989       OutEdgeIt() : Edge() { }
   990       OutEdgeIt (Invalid i) : Edge(i) { }
   991       OutEdgeIt(const NodeSet& G,const Node v)	: Edge() {}
   992     };
   993     
   994     class InEdgeIt : public Edge {
   995       friend class NodeSet;
   996     public: 
   997       InEdgeIt() : Edge() { }
   998       InEdgeIt (Invalid i) : Edge(i) { }
   999       InEdgeIt(const NodeSet& G,Node v) :Edge() {}
  1000     };
  1001 
  1002     template <typename T> class NodeMap : public DynMapBase<Node>
  1003     {
  1004       std::vector<T> container;
  1005 
  1006     public:
  1007       typedef T ValueType;
  1008       typedef Node KeyType;
  1009 
  1010       NodeMap(const NodeSet &_G) :
  1011 	DynMapBase<Node>(_G), container(_G.maxNodeId())
  1012       {
  1013 	G->dyn_node_maps.push_back(this);
  1014       }
  1015       NodeMap(const NodeSet &_G,const T &t) :
  1016 	DynMapBase<Node>(_G), container(_G.maxNodeId(),t)
  1017       {
  1018 	G->dyn_node_maps.push_back(this);
  1019       }
  1020       
  1021       NodeMap(const NodeMap<T> &m) :
  1022  	DynMapBase<Node>(*m.G), container(m.container)
  1023       {
  1024  	G->dyn_node_maps.push_back(this);
  1025       }
  1026 
  1027       template<typename TT> friend class NodeMap;
  1028  
  1029       ///\todo It can copy between different types.
  1030       ///
  1031       template<typename TT> NodeMap(const NodeMap<TT> &m) :
  1032 	DynMapBase<Node>(*m.G)
  1033       {
  1034 	G->dyn_node_maps.push_back(this);
  1035 	typename std::vector<TT>::const_iterator i;
  1036 	for(typename std::vector<TT>::const_iterator i=m.container.begin();
  1037 	    i!=m.container.end();
  1038 	    i++)
  1039 	  container.push_back(*i);
  1040       }
  1041       ~NodeMap()
  1042       {
  1043 	if(G) {
  1044 	  std::vector<DynMapBase<Node>* >::iterator i;
  1045 	  for(i=G->dyn_node_maps.begin();
  1046 	      i!=G->dyn_node_maps.end() && *i!=this; ++i) ;
  1047 	  //if(*i==this) G->dyn_node_maps.erase(i); //FIXME: Way too slow...
  1048 	  //A better way to do that: (Is this really important?)
  1049 	  if(*i==this) {
  1050 	    *i=G->dyn_node_maps.back();
  1051 	    G->dyn_node_maps.pop_back();
  1052 	  }
  1053 	}
  1054       }
  1055 
  1056       void add(const Node k) 
  1057       {
  1058 	if(k.n>=int(container.size())) container.resize(k.n+1);
  1059       }
  1060 
  1061       void erase(const Node) { }
  1062       
  1063       void set(Node n, T a) { container[n.n]=a; }
  1064       //'T& operator[](Node n)' would be wrong here
  1065       typename std::vector<T>::reference
  1066       operator[](Node n) { return container[n.n]; }
  1067       //'const T& operator[](Node n)' would be wrong here
  1068       typename std::vector<T>::const_reference 
  1069       operator[](Node n) const { return container[n.n]; }
  1070 
  1071       ///\warning There is no safety check at all!
  1072       ///Using operator = between maps attached to different graph may
  1073       ///cause serious problem.
  1074       ///\todo Is this really so?
  1075       ///\todo It can copy between different types.
  1076       const NodeMap<T>& operator=(const NodeMap<T> &m)
  1077       {
  1078 	container = m.container;
  1079 	return *this;
  1080       }
  1081       template<typename TT>
  1082       const NodeMap<T>& operator=(const NodeMap<TT> &m)
  1083       {
  1084 	copy(m.container.begin(), m.container.end(), container.begin());
  1085 	return *this;
  1086       }
  1087       
  1088       void update() {}    //Useless for Dynamic Maps
  1089       void update(T a) {}  //Useless for Dynamic Maps
  1090     };
  1091     
  1092     template <typename T> class EdgeMap
  1093     {
  1094     public:
  1095       typedef T ValueType;
  1096       typedef Edge KeyType;
  1097 
  1098       EdgeMap(const NodeSet &) { }
  1099       EdgeMap(const NodeSet &,const T &) { }
  1100       EdgeMap(const EdgeMap<T> &) { }
  1101       //      template<typename TT> friend class EdgeMap;
  1102 
  1103       ///\todo It can copy between different types.
  1104       ///
  1105       template<typename TT> EdgeMap(const EdgeMap<TT> &) { }
  1106       ~EdgeMap() { }
  1107 
  1108       void add(const Edge  ) { }
  1109       void erase(const Edge) { }
  1110       
  1111       void set(Edge, T) { }
  1112       //T get(Edge n) const { return container[n.n]; }
  1113       ValueType &operator[](Edge) { return *((T*)(NULL)); }
  1114       const ValueType &operator[](Edge) const { return *((T*)(NULL)); }
  1115 
  1116       const EdgeMap<T>& operator=(const EdgeMap<T> &) { return *this; }
  1117     
  1118       template<typename TT>
  1119       const EdgeMap<T>& operator=(const EdgeMap<TT> &m) { return *this; }
  1120       
  1121       void update() {}
  1122       void update(T a) {}
  1123     };
  1124   };
  1125 
  1126 
  1127 
  1128   ///Graph structure using a node set of another graph.
  1129 
  1130   ///This structure can be used to establish another graph over a node set
  1131   /// of an existing one. The node iterator will go through the nodes of the
  1132   /// original graph, and the NodeMap's of both graphs will convert to
  1133   /// each other.
  1134   ///
  1135   ///\warning Adding or deleting nodes from the graph is not safe if an
  1136   ///\ref EdgeSet is currently attached to it!
  1137   ///
  1138   ///\todo Make it possible to add/delete edges from the base graph
  1139   ///(and from \ref EdgeSet, as well)
  1140   ///
  1141   ///\param GG The type of the graph which shares its node set with this class.
  1142   ///Its interface must conform with \ref GraphSkeleton.
  1143   ///
  1144   ///It conforms to the graph interface documented under
  1145   ///the description of \ref GraphSkeleton.
  1146   ///\sa \ref GraphSkeleton.
  1147   ///\sa \ref NodeSet.
  1148   template<typename GG>
  1149   class EdgeSet {
  1150 
  1151     typedef GG NodeGraphType;
  1152 
  1153     NodeGraphType &G;
  1154 
  1155     class Node;
  1156     
  1157     //Edges are double linked.
  1158     //The free edges are only single linked using the "next_in" field.
  1159     struct NodeT 
  1160     {
  1161       int first_in,first_out;
  1162       NodeT() : first_in(-1), first_out(-1) { }
  1163     };
  1164 
  1165     struct EdgeT 
  1166     {
  1167       Node head, tail;
  1168       int prev_in, prev_out;
  1169       int next_in, next_out;
  1170     };
  1171 
  1172     
  1173     typename NodeGraphType::NodeMap<NodeT> nodes;
  1174     
  1175     std::vector<EdgeT> edges;
  1176     //The first free edge
  1177     int first_free_edge;
  1178     
  1179   protected:
  1180     
  1181     template <typename Key> class DynMapBase
  1182     {
  1183     protected:
  1184       const EdgeSet* G; 
  1185     public:
  1186       virtual void add(const Key k) = NULL;
  1187       virtual void erase(const Key k) = NULL;
  1188       DynMapBase(const EdgeSet &_G) : G(&_G) {}
  1189       virtual ~DynMapBase() {}
  1190       friend class EdgeSet;
  1191     };
  1192     
  1193   public:
  1194     //template <typename T> class NodeMap;
  1195     template <typename T> class EdgeMap;
  1196     
  1197     class Node;
  1198     class Edge;
  1199 
  1200     //  protected:
  1201     // HELPME:
  1202   protected:
  1203     // mutable std::vector<DynMapBase<Node> * > dyn_node_maps;
  1204     ///\bug It must be public because of SymEdgeMap.
  1205     ///
  1206     mutable std::vector<DynMapBase<Edge> * > dyn_edge_maps;
  1207     
  1208   public:
  1209 
  1210     class NodeIt;
  1211     class EdgeIt;
  1212     class OutEdgeIt;
  1213     class InEdgeIt;
  1214     
  1215     template <typename T> class NodeMap;
  1216     template <typename T> class EdgeMap;
  1217     
  1218   public:
  1219 
  1220     ///Constructor
  1221     
  1222     ///Construates a new graph based on the nodeset of an existing one.
  1223     ///\param _G the base graph.
  1224     ///\todo It looks like a copy constructor, but it isn't.
  1225     EdgeSet(NodeGraphType &_G) : G(_G),
  1226 				 nodes(_G), edges(),
  1227 				 first_free_edge(-1) { }
  1228     ///Copy constructor
  1229 
  1230     ///Makes a copy of an EdgeSet.
  1231     ///It will be based on the same graph.
  1232     EdgeSet(const EdgeSet &_g) : G(_g.G), nodes(_g.G), edges(_g.edges),
  1233 				 first_free_edge(_g.first_free_edge) { }
  1234     
  1235     ~EdgeSet()
  1236     {
  1237       // for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
  1238       //  i!=dyn_node_maps.end(); ++i) (**i).G=NULL;
  1239       for(typename std::vector<DynMapBase<Edge> * >::iterator
  1240 	    i=dyn_edge_maps.begin();
  1241 	  i!=dyn_edge_maps.end(); ++i) (**i).G=NULL;
  1242     }
  1243 
  1244     int nodeNum() const { return G.nodeNum(); }  //FIXME: What is this?
  1245     int edgeNum() const { return edges.size(); }  //FIXME: What is this?
  1246 
  1247     ///\bug This function does something different than
  1248     ///its name would suggests...
  1249     int maxNodeId() const { return G.maxNodeId(); }  //FIXME: What is this?
  1250     ///\bug This function does something different than
  1251     ///its name would suggests...
  1252     int maxEdgeId() const { return edges.size(); }  //FIXME: What is this?
  1253 
  1254     Node tail(Edge e) const { return edges[e.n].tail; }
  1255     Node head(Edge e) const { return edges[e.n].head; }
  1256 
  1257     Node aNode(OutEdgeIt e) const { return edges[e.n].tail; }
  1258     Node aNode(InEdgeIt e) const { return edges[e.n].head; }
  1259 
  1260     Node bNode(OutEdgeIt e) const { return edges[e.n].head; }
  1261     Node bNode(InEdgeIt e) const { return edges[e.n].tail; }
  1262 
  1263     NodeIt& first(NodeIt& v) const { 
  1264       v=NodeIt(*this); return v; }
  1265     EdgeIt& first(EdgeIt& e) const { 
  1266       e=EdgeIt(*this); return e; }
  1267     OutEdgeIt& first(OutEdgeIt& e, const Node v) const { 
  1268       e=OutEdgeIt(*this,v); return e; }
  1269     InEdgeIt& first(InEdgeIt& e, const Node v) const { 
  1270       e=InEdgeIt(*this,v); return e; }
  1271 
  1272 //     template< typename It >
  1273 //     It first() const { It e; first(e); return e; }
  1274 
  1275 //     template< typename It >
  1276 //     It first(Node v) const { It e; first(e,v); return e; }
  1277 
  1278     bool valid(Edge e) const { return e.n!=-1; }
  1279     bool valid(Node n) const { return G.valid(n); }
  1280     
  1281     void setInvalid(Edge &e) { e.n=-1; }
  1282     void setInvalid(Node &n) { G.setInvalid(n); }
  1283     
  1284     template <typename It> It getNext(It it) const
  1285     { It tmp(it); return next(tmp); }
  1286 
  1287     NodeIt& next(NodeIt& it) const { G.next(it); return it; }
  1288     OutEdgeIt& next(OutEdgeIt& it) const
  1289     { it.n=edges[it.n].next_out; return it; }
  1290     InEdgeIt& next(InEdgeIt& it) const
  1291     { it.n=edges[it.n].next_in; return it; }
  1292     EdgeIt& next(EdgeIt& it) const {
  1293       if(edges[it.n].next_in!=-1) { 
  1294 	it.n=edges[it.n].next_in;
  1295       }
  1296       else {
  1297 	NodeIt n;
  1298 	for(n=next(edges[it.n].head);
  1299 	    valid(n) && nodes[n].first_in == -1;
  1300 	    next(n)) ;
  1301 	it.n = (valid(n))?-1:nodes[n].first_in;
  1302       }
  1303       return it;
  1304     }
  1305 
  1306     int id(Node v) const { return G.id(v); }
  1307     int id(Edge e) const { return e.n; }
  1308 
  1309     /// Adds a new node to the graph.
  1310     Node addNode() { return G.AddNode(); }
  1311     
  1312     Edge addEdge(Node u, Node v) {
  1313       int n;
  1314       
  1315       if(first_free_edge==-1)
  1316 	{
  1317 	  n = edges.size();
  1318 	  edges.push_back(EdgeT());
  1319 	}
  1320       else {
  1321 	n = first_free_edge;
  1322 	first_free_edge = edges[n].next_in;
  1323       }
  1324       
  1325       edges[n].tail = u; edges[n].head = v;
  1326 
  1327       edges[n].next_out = nodes[u].first_out;
  1328       if(nodes[u].first_out != -1) edges[nodes[u].first_out].prev_out = n;
  1329       edges[n].next_in = nodes[v].first_in;
  1330       if(nodes[v].first_in != -1) edges[nodes[v].first_in].prev_in = n;
  1331       edges[n].prev_in = edges[n].prev_out = -1;
  1332 	
  1333       nodes[u].first_out = nodes[v].first_in = n;
  1334 
  1335       Edge e; e.n=n;
  1336 
  1337       //Update dynamic maps
  1338       for(typename std::vector<DynMapBase<Edge> * >::iterator
  1339 	    i=dyn_edge_maps.begin();
  1340 	  i!=dyn_edge_maps.end(); ++i) (**i).add(e);
  1341 
  1342       return e;
  1343     }
  1344 
  1345   private:
  1346     void eraseEdge(int n) {
  1347       
  1348       if(edges[n].next_in!=-1)
  1349 	edges[edges[n].next_in].prev_in = edges[n].prev_in;
  1350       if(edges[n].prev_in!=-1)
  1351 	edges[edges[n].prev_in].next_in = edges[n].next_in;
  1352       else nodes[edges[n].head].first_in = edges[n].next_in;
  1353       
  1354       if(edges[n].next_out!=-1)
  1355 	edges[edges[n].next_out].prev_out = edges[n].prev_out;
  1356       if(edges[n].prev_out!=-1)
  1357 	edges[edges[n].prev_out].next_out = edges[n].next_out;
  1358       else nodes[edges[n].tail].first_out = edges[n].next_out;
  1359       
  1360       edges[n].next_in = first_free_edge;
  1361       first_free_edge = -1;      
  1362 
  1363       //Update dynamic maps
  1364       Edge e; e.n=n;
  1365       for(typename std::vector<DynMapBase<Edge> * >::iterator
  1366 	    i=dyn_edge_maps.begin();
  1367 	  i!=dyn_edge_maps.end(); ++i) (**i).erase(e);
  1368     }
  1369       
  1370   public:
  1371 
  1372 //     void erase(Node nn) {
  1373 //       int n=nn.n;
  1374 //       int m;
  1375 //       while((m=nodes[n].first_in)!=-1) eraseEdge(m);
  1376 //       while((m=nodes[n].first_out)!=-1) eraseEdge(m);
  1377 //     }
  1378     
  1379     void erase(Edge e) { eraseEdge(e.n); }
  1380 
  1381 //     //\bug Dynamic maps must be updated!
  1382 //     //
  1383 //     void clear() {
  1384 //       nodes.clear();edges.clear();
  1385 //       first_node=first_free_node=first_free_edge=-1;
  1386 //     }
  1387 
  1388   public:
  1389     class Node : public NodeGraphType::Node {
  1390       friend class EdgeSet;
  1391       //      template <typename T> friend class NodeMap;
  1392       
  1393       friend class Edge;
  1394       friend class OutEdgeIt;
  1395       friend class InEdgeIt;
  1396       friend class SymEdge;
  1397 
  1398     protected:
  1399       friend int EdgeSet::id(Node v) const; 
  1400       //      Node(int nn) {n=nn;}
  1401     public:
  1402       Node() : NodeGraphType::Node() {}
  1403       Node (Invalid i) : NodeGraphType::Node(i) {}
  1404       Node(const typename NodeGraphType::Node &n) : NodeGraphType::Node(n) {}
  1405     };
  1406     
  1407     class NodeIt : public NodeGraphType::NodeIt {
  1408       friend class EdgeSet;
  1409     public:
  1410       NodeIt() : NodeGraphType::NodeIt() { }
  1411       NodeIt (Invalid i) : NodeGraphType::NodeIt(i) {}
  1412       NodeIt(const EdgeSet& _G) : NodeGraphType::NodeIt(_G.G) { }
  1413       NodeIt(const typename NodeGraphType::NodeIt &n)
  1414 	: NodeGraphType::NodeIt(n) {}
  1415       operator Node() { return Node(*this);}
  1416     };
  1417 
  1418     class Edge {
  1419       friend class EdgeSet;
  1420       template <typename T> friend class EdgeMap;
  1421 
  1422       //template <typename T> friend class SymEdgeSet::SymEdgeMap;      
  1423       //friend Edge SymEdgeSet::opposite(Edge) const;
  1424       
  1425       friend class Node;
  1426       friend class NodeIt;
  1427     protected:
  1428       int n;
  1429       friend int EdgeSet::id(Edge e) const;
  1430 
  1431       Edge(int nn) {n=nn;}
  1432     public:
  1433       Edge() { }
  1434       Edge (Invalid) { n=-1; }
  1435       bool operator==(const Edge i) const {return n==i.n;}
  1436       bool operator!=(const Edge i) const {return n!=i.n;}
  1437       bool operator<(const Edge i) const {return n<i.n;}
  1438       ///\bug This is a workaround until somebody tells me how to
  1439       ///make class \c SymEdgeSet::SymEdgeMap friend of Edge
  1440       int &idref() {return n;}
  1441       const int &idref() const {return n;}
  1442     };
  1443     
  1444     class EdgeIt : public Edge {
  1445       friend class EdgeSet;
  1446     public:
  1447       EdgeIt(const EdgeSet& G) : Edge() {
  1448 	//      	typename NodeGraphType::Node m;
  1449         NodeIt m;
  1450 	for(G.first(m);
  1451 	    G.valid(m) && G.nodes[m].first_in == -1;  G.next(m));
  1452 	n = G.valid(m)?-1:G.nodes[m].first_in;
  1453       }
  1454       EdgeIt (Invalid i) : Edge(i) { }
  1455       EdgeIt() : Edge() { }
  1456       ///\bug This is a workaround until somebody tells me how to
  1457       ///make class \c SymEdgeSet::SymEdgeMap friend of Edge
  1458       int &idref() {return n;}
  1459     };
  1460     
  1461     class OutEdgeIt : public Edge {
  1462       friend class EdgeSet;
  1463     public: 
  1464       OutEdgeIt() : Edge() { }
  1465       OutEdgeIt (Invalid i) : Edge(i) { }
  1466 
  1467       OutEdgeIt(const EdgeSet& G,const Node v) : Edge(nodes[v].first_out) { }
  1468     };
  1469     
  1470     class InEdgeIt : public Edge {
  1471       friend class EdgeSet;
  1472     public: 
  1473       InEdgeIt() : Edge() { }
  1474       InEdgeIt (Invalid i) : Edge(i) { }
  1475       InEdgeIt(const EdgeSet& G,Node v) :Edge(nodes[v].first_in) { }
  1476     };
  1477 
  1478     template <typename T> class NodeMap : public NodeGraphType::NodeMap<T>
  1479     {
  1480     public:
  1481       NodeMap(const EdgeSet &_G) :
  1482 	NodeGraphType::NodeMap<T>(_G.G) { }
  1483       NodeMap(const EdgeSet &_G,const T &t) :
  1484 	NodeGraphType::NodeMap<T>(_G.G,t) { }
  1485       //It is unnecessary
  1486       NodeMap(const typename NodeGraphType::NodeMap<T> &m)
  1487 	: NodeGraphType::NodeMap<T>(m) { }
  1488 
  1489       ///\todo It can copy between different types.
  1490       ///
  1491       template<typename TT>
  1492       NodeMap(const typename NodeGraphType::NodeMap<TT> &m)
  1493 	: NodeGraphType::NodeMap<T>(m) { }
  1494     };
  1495     
  1496     template <typename T> class EdgeMap : public DynMapBase<Edge>
  1497     {
  1498       std::vector<T> container;
  1499 
  1500     public:
  1501       typedef T ValueType;
  1502       typedef Edge KeyType;
  1503 
  1504       EdgeMap(const EdgeSet &_G) :
  1505 	DynMapBase<Edge>(_G), container(_G.maxEdgeId())
  1506       {
  1507 	//FIXME: What if there are empty Id's?
  1508 	//FIXME: Can I use 'this' in a constructor?
  1509 	G->dyn_edge_maps.push_back(this);
  1510       }
  1511       EdgeMap(const EdgeSet &_G,const T &t) :
  1512 	DynMapBase<Edge>(_G), container(_G.maxEdgeId(),t)
  1513       {
  1514 	G->dyn_edge_maps.push_back(this);
  1515       } 
  1516       EdgeMap(const EdgeMap<T> &m) :
  1517  	DynMapBase<Edge>(*m.G), container(m.container)
  1518       {
  1519  	G->dyn_edge_maps.push_back(this);
  1520       }
  1521 
  1522       template<typename TT> friend class EdgeMap;
  1523 
  1524       ///\todo It can copy between different types.
  1525       ///
  1526       template<typename TT> EdgeMap(const EdgeMap<TT> &m) :
  1527 	DynMapBase<Edge>(*m.G)
  1528       {
  1529 	G->dyn_edge_maps.push_back(this);
  1530 	typename std::vector<TT>::const_iterator i;
  1531 	for(typename std::vector<TT>::const_iterator i=m.container.begin();
  1532 	    i!=m.container.end();
  1533 	    i++)
  1534 	  container.push_back(*i);
  1535       }
  1536       ~EdgeMap()
  1537       {
  1538 	if(G) {
  1539 	  typename std::vector<DynMapBase<Edge>* >::iterator i;
  1540 	  for(i=G->dyn_edge_maps.begin();
  1541 	      i!=G->dyn_edge_maps.end() && *i!=this; ++i) ;
  1542 	  //if(*i==this) G->dyn_edge_maps.erase(i); //Way too slow...
  1543 	  //A better way to do that: (Is this really important?)
  1544 	  if(*i==this) {
  1545 	    *i=G->dyn_edge_maps.back();
  1546 	    G->dyn_edge_maps.pop_back();
  1547 	  }
  1548 	}
  1549       }
  1550       
  1551       void add(const Edge k) 
  1552       {
  1553 	if(k.n>=int(container.size())) container.resize(k.n+1);
  1554       }
  1555       void erase(const Edge) { }
  1556       
  1557       void set(Edge n, T a) { container[n.n]=a; }
  1558       //T get(Edge n) const { return container[n.n]; }
  1559       typename std::vector<T>::reference
  1560       operator[](Edge n) { return container[n.n]; }
  1561       typename std::vector<T>::const_reference
  1562       operator[](Edge n) const { return container[n.n]; }
  1563 
  1564       ///\warning There is no safety check at all!
  1565       ///Using operator = between maps attached to different graph may
  1566       ///cause serious problem.
  1567       ///\todo Is this really so?
  1568       ///\todo It can copy between different types.
  1569       const EdgeMap<T>& operator=(const EdgeMap<T> &m)
  1570       {
  1571 	container = m.container;
  1572 	return *this;
  1573       }
  1574       template<typename TT>
  1575       const EdgeMap<T>& operator=(const EdgeMap<TT> &m)
  1576       {
  1577 	copy(m.container.begin(), m.container.end(), container.begin());
  1578 	return *this;
  1579       }
  1580       
  1581       void update() {}    //Useless for DynMaps
  1582       void update(T a) {}  //Useless for DynMaps
  1583     };
  1584 
  1585   };
  1586 
  1587 /// @}  
  1588 
  1589 } //namespace hugo
  1590 
  1591 #endif //HUGO_LIST_GRAPH_H